Corrosive inhibited additive for mineral lubricating oil composition



Patented Nov. 18, 1947 CORROSIVE ITED ADDITIVE MIN- ERAL LUBBICATING OIL COMPOSITION John C. Zimmer and George M. McNulty, Union,

N. 3., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application March 11, 1944, Serial No. 526,129

(01. eta-51) 18 Claims.

This invention relates to agents which are added to mineral lubricating oils to impart film; strengthening properties to such oils, and it relates more particularly to a method of stabilizing such agents during storage and transportation.

In the lubrication of hypoid and other gears, various materials containing chlorine or other halogens are used alone or in combination with other materials effective in increasing the extreme pressure lubricant characteristics of the composition, such as sulfur and phosphorus compounds. These compositions have a serious disadvantage, however, in that they tend to rust the metal surfaces which are being lubricated. They also cause corrosion and staining of ferrous and copper-bearing alloys used in bearings, bushings, pistons, etc. Also, the us in cutting fluids of sulfur or sulfur compounds, alone or in the presence of chlorine compounds, usually causes a black stain of copper sulfide on copper alloys.

In our U. S. Patent 2,340,036 it is disclosed that thisundesirable corrosion and staining of metals can be prevented by adding to the extreme pressure lubricant a small proportion of an oil-soluble salt of an autocondensation product of a hydroxyarylallgvl amine We have now discovered that salts of this type may vary advantageously be added to the extreme pressure agent itself, when the same contains a halogen in a form which tends to produce a hydrohalogenic acid under storage conditions, or when the agent contains both a halogen and another material such as active sulfur. The addition of the preferred salt serves the double purpose of preventing corrosion of metallic containers during storage and of preventing the deterioration of the extreme pressure promoting properties of the agent itself.

The use of the salts of the hydroxyarylalkyl amine condensation products in accordance with the present invention has a distinct advantage over the use of other compounds which have been found to be useful in preventing deterioration of the extreme pressure lubricant containing the mineral oil base. Compounds which are effective in the blended lubricating oil include compounds of the amine type, typified by dicyclohexylamine, as disclosed in our U. S. Patent 2,268,608. While such materials are indeed effective in preventing the corrosion of metal parts in contact with extreme pressure lubricants containing active chlorine and sulfur, materials of this type are not suitable for use as corrosion preventives for the extreme pressure agents themselves or concentrates of the same. This is because the amines form insoluble hydrochlorides with the active chlorine of the extreme pressure agent and precipitate out in large volume. By contrast, the preferred salts of the present invention may be effectively used with the extreme pressure agents and their concentrates during a period or storage in metallic containers without the disadvantage of such precipitation. The hydrochlorides which may be formed are soluble. The salts may be added to the extreme pressure agents in quantities which will not only protect the agent itself during storage and transportation but will protect the extreme pressure lubricant after final blending with the lubricating oil base.

The extreme pressure agents which may be advantageously stabilized by the preferred salts of the present invention include in general any extreme pressure agent comprising an organic material containing a halogen in such form and in such quantity as to be capable of substantially increasing the load-carrying capacity of the oil to which it may be added but which tends to form a hydrohalogenic acid under storage conditions. Such materials include: halogenated hydrocarbons; halogenated hydrocarbons also substituted by oxygen-containing groups, e. g. halogenated fatty acids; halogenated hydrocarbons which have been reacted with sodium sulfide, sodium hydrosulfide, sodium mercaptides, sodium xanthate and the like to introduce sulfur into the molecule; combinations of sulf urized fatty oils and chlorinated wax: halogenated hydrocarbons in admixture with elementary sulfur; and the like. Particularly useful are the agents prepared by reaction of a chlorinated kerosene or chlorinated paraifin wax with a sodium sulfide or sodium mercaptide according to the methods described in U. S. Patents 2,124,598 and 2,311,500. For economic reasons chlorine is the preferred halogen to be used in such agents. It is in general preferable to use in extreme pressure lubricants an agent containing 5-50% of chlorine and 3-15% of sulfur, when such agents are to be diluted by nine times their volume of lubricating have been caused to undergo autocondensation whereby the products become oil soluble and exhibit more potent corrosion inhibiting properties than the uncondensed amines. The salts of such material are likewise more potent than the salts of the uncondensed amines. Typical compounds are obtained by condensing an alkyl phenol with an aldehyde, e. g. formaldehyde, in the presence of hydrogen chloride, then reacting the resulting phenolic condensation product with ammonia or with an organic nitrogen base, heating the amino compound thus formed to liberate a portion of the nitrogen content of the same and finally reacting the condensed amine compound with a suitable metallic base such as barium hydroxide. The solubility of the amino compounds in hydrocarbon oils, as well as the solubility of the salts obtained from them, varies with the degree of condensation or resiniflcation,

' and their solubility and eflectiveness are readily increased by subjecting them to auto-condensation conditions during their preparation, or by subjecting the simple amino reaction products to condensation treatment after they have been prepared. The increase in the oil solubility of the final products is desirable in that it makes possible the preparation of liquid concentrates containing relatively large proportions, such as 25% or more, of the improving agents of this invention dissolved in hydrocarbon oil, these concentrated solutions being conveniently used for blending purposes. It may be noted that the oil solubility of the products also increases with the length of the alkyl substituent in the aromatic nucleus. In'general, the uncondensed hydroxyarylalkyl amine should contain an alkyl side chain of at least four carbon atoms.

The invention thus contemplates the use as improving agents for halogenated extreme pressure agents and concentrates of the same of salts of high molecular weight resinous autocondensation products of hydroxyarylalkyl amine which preferably have the characteristic structure.

. x- R-N \R n in which R i an alkyl linkage such as in which R' is either hydrogen or a substituted or unsubstituted alkyl or aryl group, X is hydrogen or at least one organic radical attached to the aryl nucleus, especially an alkyl, aryl or aralkyl radical which in turn may contain substituent groups, R and R" are hydrogen or alkyl or aryl radicals or substituted alkyl or aryl radicals, and n is a small whole number. The desired compounds are also characterized by having at least four carbon atoms in alkyl groups joined to the aryl nucleus and/or to the amine radical and are further characterized in having undergone an autocondensation reaction to produce a resinous viscous liquid-to-solid product of high molecular weight which is soluble in hydrocarbon oils. In this, as in all the other structural formulae given in this specification, the location of the substituent radicals attached to the aryl nucleus is given merely as an illustration, and the various substituent radicals may be attached at any positions on the aryl nucleus, ortho, meta and/or para to the hydroxyl group and to each other. The more preferred compounds for use according to this invention come within the above definition and are salts of resinous autocondensation products of materials having the characteristic structure in which R is an alkyl group of at least 4 and preferably 5-20 or more carbon atoms, the compound having undergone an autocondensation reaction as described above. The alkali and alkaline earth metal salts of these resinous products are especially useful, but salts of other divalent metals such as zinc, tin, cadmium and lead should be particularly mentioned. Also, salts containing basic radicals, instead of metals, such as onium salts, e. g. the ammonium, alkyl-ammonium, sulfonium, phosphonium and pyridonium salts, may be used to advantage.

The autocondensation of the hydroxylaryl amino compounds described above may be accomplished by heating. The extent of heating required varies with the composition of the particular amine being treated, some needing only 4 to 6 hours, but others requiring 15 to 20 hours of heating at a, temperature of to C. In some cases the heating time is shortened by using higher temperatures. It has been found that when the amines are formed by first reacting a phenol with an aldehyde in the presence of hydrogen chloride, and then treating the reaction product with ammonia, the time required for heating the final product varies with the chlorine content of the intermediate and increases with increase in chlorine content. Products formed from intermediates containing from 10 to 15%, preferably 12% to 14%, of chlorine are much desired, as the condensed nitrogenous products formed from them are very effective lubricating oil improving agents. The condensation of the amines may be brought about not only by heating, but by standing at room temperature for a long period of time. Heating greatly hastens the autocondensation process, however. The heating may be carried out at atmospheric pressure or at higher pressures. It is often convenient to seal the compound in a bomb and conduct the heating under the pressure developed at 110 to 120 C. Whether the condensation is caused by heating or long standing, a characteristic change in the product is the elimination of substantial amounts of nitrogen, the quantities eliminated ranging from 10% to 75% of the original nitrogen content, depending upon conditions.

As stated above, the hydroxyarylalkyl amines used to form the desired resinous products of l the present invention may be readily prepared by reacting a phenol with an aldehyde in the presence of hydrogen chloride to form a hydroxybenzyl chloride or like product and then reacting this product with ammonia or with an amine. The reaction for the preparation of the chlorinated product goes with great ease, even 900' grams of paraformaldehyde (30 mols of formaldehyde) and 5000 grams of concentrated hydrochloric acid were placed in a 12-liter flask provided with a stirrer, a reflux condenser and a thermometer. A solution of 2060 grams mols) of ptert.=-octyl phenol in an equal weight of benzene was then added to the flask over a period of 20 to 25 minutes, while passing dry hydrogen chloride gas continuously through the solution during the entire reaction in order to keep the mixture saturated with hydrogen chloride. The stirrer was also operated continuously to provide eflicient contact between the two liquid phases during the reaction. The temperature of the initial mixture of paraformaldehyde and hydrogen chloride was C. It increased to 45-50 C. upon addition of the phenol and this temperature was thereafter maintained for 1 hours while constantly stirring. and passing in hydrogen chloride gas. At the end of this time, after the stirring was stopped, an upper phenolic benzene layer separated from a lower fuming hydrochloric acid layer and was separately withdrawn from the reaction vessel. A portion of the upper layer, after washing and removal of the benzene, yielded a viscous light red oil, crystallizing partly on standing. Analysis of a small sample of this oil indicated it to contain 14.2% chlorine.

To 600 grams of the above benzene solution there was slowly added (with thorough stirring) 50 grams of anhydrous ammonia dissolved in 300 grams of 98% isopropyl alcohol, Since this reaction takes place with great evolution of heat, cooling or pressure is advisable to prevent loss of solvent and ammonia, especially in large scale preparations. After complete addition of the ammonia, the mixture consisted of a thick, tacky, yellow slurry containing an excess ,(about 10%) of ammonia. This mixture was then placed in a stainless steel bomb of one liter capacity, which was sealed and then heated for hours at a temperature of 110 to 120 C.

After heating, the reaction product was obtained as a material completely soluble in the benzene-alcohol solvent present which also contained a fine suspension of insoluble ammonium chloride. This mixture was washed with water several times to remove both the alcohol and the suspended salt. 500 grams of a refined parafiinic lubricating oil, having a viscosity Saybolt at 210 F. of 43 seconds, was added and the mixture was blown with nitrogen at 120 to 130 C. for two hours to remove the benzene. After this, more oil was added to provide a concentrate of relatively low viscosity and clear red color containing of the reaction product.

A small portion of the benzene solution was withdrawn for analysis prior to addition of the lubricating oil. Evaporation of the benzene produced a brittle, resinous material containing 2.8% nitrogen.

The chlorine content of the intermediate product may be controlled by the ratio of the formaldehyde and phenol used in the initial reaction. For example, when conducting the process as described in Example 1 with several different proportions of formaldehyde and tert.- octyl phenol, the chlorine content of the intermediate product and the nitrogen content of the final product were observed to be as follows:

Intermediate Product Per Cent Cl Final Prod- Molal 3.21%; t0:51];rmiildehyde to ct i; Cent henol Instead of removing the suspended ammonium chloride from the heat treated reaction product by water washing as described in Example 1, the salt may be removed by filtration, preferably by filter pressing the suspension with the addition of a filter aid such as Hyflo. A suitable lubricating oil may then be added to the filtrate (if it is desired to produce directly an oil solution of the final product), and the alcohol-benzene solvent may then be removed by distillation.

Although a very satisfactory procedure for preparing the resinous product has been described with reference to the condensation of a nitrogen base with a condensation product of an alkyl phenol, formaldehyde and hydrogen chloride, and further condensation or polymerization of the resulting product, it is to be understood that other procedures may be employed forobtaining oil blending agents of similar character. However, the described method is preferred. In these procedures the order of the reaction steps may be changed and other similar reactants may be used. For example, the formaldehyde or other aldehyde may be first reacted with ammonia, or with a primary, secondary or tertiary amine, to form alkyl-alkylol amines for condensation with a phenol or an alkyl phenol; or it may be desired to alkylate the base or the base derivatives of the phenol condensation product, e. g., with an alkylating agent such as diethyl sulfate, an allwl halide, an alcohol, ketone or olefin. by known alkylating methods, and with subsequent reduc tion by hydrogen, if needed or desired. Since formaldehyde and ammonia react readily to form hexamethylenetetramine, the latter material may be advantageously reacted directly with an alkylated phenol.

As in the case of many resin preparations, the exact mechanism of the reaction is not entirely understood. In the first stage the alkyl phenol may be regarded as condensing with the reaction product of the hydrogen halide and aldehyde, or as condensing with formaldehyde, the condensation product thereof being condensed with the hydrogen halide. The resulting product of this reaction is a complex mixture of various chlormethyl derivatives having the following general formula:

in which the substituent groups may be attached to any position of the aryl nucleus indicated diagrammatically by the hexagon, R representing a hydrocarbon group of at least two, and preferably an alkyl group of four or more, carbon atoms, and X representing hydrogen or an organic radical, especially an alkyl, aryl or aralkyl radical which may in turn contain substituent groups. Among the compounds which have been identified as present in the products from such reaction are the following:

' CHzCl chlormethyl tert.-octyl phenol ClHnC CHzCl C sHn di(chlormethyl) tert.-octyl phenol OH OH Omen-mm CaHn aHu chlormethyl bis (tert.-octyl hydroxy phenyl) methane, and

OH on ClHzCUCHrOCHzCl CnGn CBHn bis (tert.-octyl chlormethyl hydroxy phenyl) methane In the second stage of reaction, the condensation products of the alkyl phenol, formaldehyde and hydrogen halide split ofi halogen in undergoing a further condensation with the nitrogen base, and thu the alkyl phenol radical becomes united with the base radical through the methylene (CH2) group, thereby forming compounds containing the following characteristic group:

wherein R represents at least one alkyl group substituent in the aromatic nucleus Ar, the alkyl group containing at least four carbon atoms, the subscript n represents an integer from 1 to 3, and X represents a nitrogen base radical in which the nitrogen is linked to the methylene group or groups. Illustrative types of compounds included within the above formula are the following:

paraformaldehyde in a solvent such as benzene until most of the formaldehyde has reacted with the hydrogen chloride to give av soluble reaction product. The entire reaction mixture is then mixed with an alkyl phenol to give an alkylated hydroxy benzyl chloride or condensation products of the same, the reagents being used preferably in a ratio of about 2.5 mol equivalents of formaldehyde per mole of phenol. This intermediate is reacted with ammonia and heated as in Example 1 to give an oil-soluble product. The chlormethyl ether may also be prepared by any other suitable method and the mixed ether products may be fractionated to separate pure ethers, any one of which maybe reacted with the phenol. The phenol may also be added to the formaldehyde-benzene mixture and dry hydrogen chloride passed through this mixture to obtain the desired product in a single stage reaction. This product is reacted with ammonia and heated as before to give the lubricating oil additive.

The reaction of hydrogen chloride and formaldehyde may also be conducted in the presence of an alcohol, for example, methyl alcohol. to give an alpha chlorether. This may be done by passing dry hydrogen chloride into a suspension of paraformaldehyde in the alcohol. This ether may then be reacted with the alkyl phenol by heating with or without a catalyst, such as zinc chloride, to give the alkyl hydroxy benzyl chloride, the original alcohol being regenerated as a by-product.

Also, the alkyl phenol may be converted to the sodium salt and this salt, with no excess of alkali present, may then be caused to react with an aldehyde to give an alkylol derivative. This may be converted to the chloride by reaction with hydrogen chloride. Either the alkylol derivative or a resulting halide derivative may then be reacted with ammonia and heated as in Example 1 to give an oil-soluble product. This is illustrated in the following example.

Example 2 One molecular proportion each of tert.-octyl phenol (tetramethyl butyl phenol) and of sodiumhydroxide are dissolved in water containing sumcient alcohol to dissolve the resulting sodium phenolate. The use of about 2 volumes of water and volume of methyl alcohol per volume of phenol is suflicient for this purpose. Three molecular proportion of formaldehyde (in the form of formalin containing 37% CHzO) are added to this solution and the mixture allowed to stand for about 48 hours at room temperature, the reactionleading to the formation of the dimethylol derivative. The reaction mixture is then neutralized with acetic acid or any suitable mineral acid and the liberated di(hydroxymethyl) tert.-octyl phenol separates as an upper layer and may be used directly as such or after purification. To form the dichloride, the di(hydroxymethyl) tert.-octyl phenol may be contacted with concentrated aqueous hydrochloric acid, or with dry hydrogen chloride. In the latter instance the hydrogen chloride may be passed through a solution of the compound in a suitable solvent such as benzene, carbon tetrachloride, chloroform, etc.

The reaction with ammonia may be carried out by adding an excess of ammonia, dissolved in isopropyl alcohol, to a solution of the hydroxy methyl tert.-octyl phenol or of the corresponding chloride in a solvent such as benzene. This reaction with ammonia is quite violent at first and is conducted in the same manner as described in Example 1. When the addition of ammonia is completed, the reaction mixture is sealed in a bomb and heated at 110 to 120 C. for about 18 to 24 hours. The mixture is subsequently washed with water to remove isopropyl alcohol and ammonium chloride and the benzene solvent is then evaporated to recover the complex reaction product as a brittle solid resin which is soluble in lubricating oils. Because of its resinous nature, the rate of solution of the product in oil may be slow, particularly in base stocks of high viscosity index. To facilitate solution in such oils it is advisable to heat them to above 60-70 C. when preparing blends of the addition agent. This procedure may also be used to prepare concentrates containing as much as 25 to 75% of the material, the concentrates later being mixed with additional base stock to give finished blends of the desired concentration. 1

It is possible to conduct the reaction of the phenol, formaldehyde and ammonia directly in a single stage by placing a mixture of suitable proportions of these reagents in a bomb and heating it, for example, at 110 to 140 C. for about 15 to 20 hours. The proportions of reagents are preferably similar to those used in the process described above, at least a mol equivalent of formaldehyde and ammonia being used per mol of phenol. The ammonia is preferably in excess,

some remaining at the end of the reaction. This is illustrated in the following example.

Example 3 A stainless steel bomb was charged with 51.5 grams of p-tert.-octyl phenol. Then 20 grams of 37% strength aqueous formaldehyde and 25 cc. of concentrated aqueous ammonia were added and the bomb was quickly sealed. The bomb was heated to 120 C. and held at this temperature for 16 hours, after which it was cooled and opened and the reaction mixture poured into water. The product was extracted with ether, and the ether extract was washed free of ammonia and subsequently dried over sodium sulfate. After the ether was removed by evaporation, there remained 50.5 grams of a soft red resin which contained 1.3 nitrogen.

Two further examples, showing somewhat varied procedures, are as follows:

Example 4 A stainless steel bomb was charged with 150 cc. of absolute ethyl alcohol and 7.5 grams of trioxymethylene. The solution was then saturated with ammonia gas at 0 C., the trioxymethylene being dissolved during the process of saturation. 17.5 grams of ammonia were absorbed, 55.5 grams of tert.-octyl phenol were then added, and the bomb was quickly closed and heated at 110 C. for 20 hours. The bomb was then cooled, opened, and the reaction mixture poured into water and extracted with ether. The ether extract was washed free of ammonia with water and then dried over sodium sulfate. Evaporation of the ether yielded 62 grams of a soft light colored resin, which upon analysis was found to contain 2.52% nitrogen. Upon heating this material at 200 C. for one-half hour under 3 mm. absolute pressure and then cooling, a brittle resin was obtained which had a, nitrogen content of 0.56%. A portion of this material was then blended in 0.1% concentration with a turbine oil which 10 normally caused heavy corrosion in a turbine oil corrosion test. The blend showed only very slight corrosion in this test and in fact this additive was found to be substantially as efiective as the best anti-corrodants known.

Example 5 A steel, open top vessel was charged with 45 grams of paraformaldehyde, 112 grams p-tert.- octyl phenol, and 120 grams of a 45 vis./210 F. S. S. U. mineral oil. Mechanical agitation was used, and the mixture was heated to about 110- 115 F., at which temperature anhydrous ammonia was passed in. The temperature rose spontaneously to 150 F., and then gradually dropped to 100 F., at which point the passage of the ammonia gas was discontinued. The temperature was then gradually increased to 300 F., and held there for 3 hours. The product was allowed to cool to 80 F., and was a heavy, dark red, viscous material containing 1.9% nitrogen. By virtue of the mineral oil content of the product, it can be handled as a liquid when the temperature reaches 125 F.

As a further variation of these processes, hexamethylenetetramine may be used in place of a mixture of formaldehyde and ammonia and may be reacted by heating with a phenol with or without a solvent. This is illustrated by the following example.

Example 6 410 lbs. of diamyl phenol (1.8 mols) and 50 lbs. of hexamethylenetetramine (0.4 mol) were charged into a steel reaction tank fitted with steam coils. The mixture was heated by gradually raising the pressure in the steam coils. At about 200 F. (93 C.) the reaction began. After further gradual heating to about 300 F. (149 C.) over period of 3 /2 hours a, product was formed which, on cooling, was an amber colored resinous material readily soluble in mineral lubricating oil and contained about 3.4% of nitrogen.

Primary and secondary amines and substituted amines, such as diethyl amines, diamyl amines, piperidine, aniline, diphenyl amine, and substituted amines, such as ethanolamine and the like, may be substituted for the ammonia in any of the above described processes to prepare similar condensation products. These upon heating also undergo further condensation and polymerization.

methods and may be reacted with ammonia or a primary or secondary amine and heated to secure resinous condensation and polymerization products suitable for use in preparing the salts of the present invention. Examples of such hydroxy benzyl chlorides are and OH OH ClHaC CH CHIGI Hydrobenzylamines, such as those having the characteristic structure 011 /R' CHz-N are illustrated by the following example:

Example 7 Dlethyl amino methyl tert.-octyl phenol, (CaHa) 2NCII2-C8H1TCBH3OH was prepared by reaction of equimolal amounts of ethoxy methyl diethyl amine, (C2H5)2NCH2OC2H5 (reaction product of diethylamine and formaldehyde in the presence of ethyl alcohol) with tert.-octyl phenol at the temperature of the steam bath for 24 hours. The product was distilled under 3 mm. mercury absolute pressure, yielding a clear liquid distillate fraction at 163 to 165 C. and a residue which was a yellow, transparent, hard resin. This resin was found to be active as an anti-corrodant in a'turbine oil corrosion test, although it was not quite as eflective as the products of Examples 3 and 4.

The phenols used in any of the above described processes include generally all nuclearly hydroxylated aromatic compounds having phenolic properties and a. readily replaceable-nuclear hydrogen atom which is preferably-either ortho or para to the hydroxyl group. Phenols extracted from petroleum oils may also be used as obtain-ed or after alkylation. Also, other naturally occurring phenols may be used, such as those having a vegetable orgin, for example, car-danol, obtained from cashew nut shells. As indicated above, it is preferred that the phenols contain an alkyl group of at least two, and preferably four or more, carbon atoms attached to the nucleus. This may be accomplished by alkylating any of the above-described phenols which do not already contain suitable alkyl groups. The alkyl phenols may be prepared by alkylation of phenols with olefins, including mixtures of olefins such as those obtained in cracked petroleum fractions, and by alkylation of phenols with alkyl halides, including chlorinated paraflin wax and chlorinated petrolatums derived from petroleum. Such chlorinated waxes may contain dichlorides and polychlorides and may be used in alkylating phenols by the-customary Friedel-Crafts type of synthesis to give complex alkylated phenols of high molecular weight in which several phenol groups are linked by alkyl radicals in a single molecule. These high molecular weight complex alkyl phenolic products, when reacted with an aldehyde and a nitrogen base as described herein, give products which are effective in reducing the pour point of waxy oils and in raising the viscosity index of lubricating oils as well as in improving their lubricating properties, such as film strength, and their stability and resistance to oxidation.

In addition to the phenols, other hydroxy aromatic compounds may be employed in forming the hydroxyarylalkyl amines, For example, alkylated phenol sulfides or disulfides may be employed. These may be reacted. wit q mfi qshyde and hydrogen chloride or with chlormethyl ethers to form chlorinated products of the type in which R is preferably an alkyl radical, and these products may be reacted with ammonia. or amines and resinifled in accordance with the present invention; or the phenol sulfides may be reacted directly with analdehyde and ammonia or an amine or with hexamethylenetetramine.

Other hydroxy aromatic compounds may also be used in a similar manner, such as naphthols, hydroxybiphenyl, thymol, etc.

The foregoing description has related to methods of preparing the resinous autocondensation products of hydroxyarylalkyl amines. The metallic salts of these products may be readily prepared by reacting the products with metallic bases, alcoholates, etc. For example, the octyl phenol e formaldehyde-hydrogen chloride-ammonia product of Example 1 may be reacted with barium hydroxide by heating with a dispersion of the latter in mineral oil or benzene to form a barium salt in which the metal replaces hydrogen of a hydroxy group. The same material may be reacted with an alcoholate, such as magnesium methylate or ethylate; or it may be reacted with an alkali, and the alkali salt so formed may be converted into other metallic salts by double decomposition, as in reacting with a salt of another metal. Chlorides of polyvalent metals, such as magnesium; zinc and the like, work satisfactorily in the double decomposition, which is preferably conducted in absolute alcohol as the reaction medium. In preparing barium salts by this method, barium bromide will be found to be a more satisfactory reagent than the chloride becaue of its better solubility in alcohol. In general, about 5 to 10% excess metal hydroxide over the amount theoretically required will be sufficient for conversion of the condensation products to their metal salts, but greater excesses than this may be necessary depending on reaction conditions and the particular products being handled.

Although in the preferred method of the present invention autocondensation of the hydroxyarylakyl amines is first effected before conversion to the metal salts, it may be found desirable in some instances to form the metal salt of the hydroxyarylalkyl amine before bringing about autocondensation.

The onium salts of the resinous products of hydroxyarylalkyl amines may be prepared by reacting a halide of an onium base, e. g., a tetraalkyl' ammonium chloride, a sulfonium chloride, or the like, with an alkali metal salt of the resinous hydroxyarylalkyl amine, preferably in an alcoholic solution. The alkali halide formed in the reaction is insoluble and may be conveniently removed.

The preparation of the salts from the compounds containing free hydroxy groups is illusbarium" salt in benzene.

trated by the following example of the preparation of a barium salt:

Example 8 145 grams of the ammonia derivative of chloromethyl tert.- octyl phenol, prepared, for example, by the method shown in Example 1, and 145 grams of C. P. benzene were refluxed with 215 grams of Ba(OH)2.8I-I2O for 60 hours, water being removed from the reaction through a trap in the reflux condenser. The mixture was filtered to give an approximately 50% solution of the Analysis showed the product, on a benzene-free basis, to contain 11.13% of barium. A product containing 10.87% barium on a solvent-free basis may, however, be

obtained by refluxing the mixture for only 8 hours. The product on complete removal of the solvent was a brown powdery mass.

A detailed procedure for conducting a small scale commercial preparation of a typical anticorrosive agent of the present invention will be described in the example which follows. In this example paraformaldehyde is reacted with hydrog'en chloride, the product is reacted with tart.- octyl phenol, the product thereby formed is further reacted with ammonia, and the amino compound thus produced is finally converted into the barium salt.

Example 9 2060 grams of 100% commercial grade benzene (the weight being equal to that of 10 mols of tert.- octyl phenol) and 750 grams (25 mols) of paraformaldehyde are introduced into a nickel agitator and the stirrer started. Dry hydrogen chloride gas is introduced through a tube extending to the bottom of the reactor, with perforations .near the lower end of the tube. The gas is passed out through a wash bottle containing a liquid hydrocarbon such as ben'zol or a petroleum fraction in order to observe the rate of flow, and thus to a fume hood, maintaining the reactor at atmospheric pressure. After the air is expelled, the gas is passed in slightly faster than it can be absorbed in order to hydrohalogenate as rapidly as possible, maintaining the temperature at about 20 to 30 C. by circulating water through the jacket. After one hour the gas flow is stopped. 2060 grams (10 mols) of tert.-octyl phenol which have been melted by means of a steam coil are added to the same reactor, or to another reaction vessel to which the entire product has been transferred, through a dropping funnel or other suitable means, as rapidly as possible, holding the temperature in the reactor below 50 C. The fiow of hydrogen chloride gas is resumed immediately at a rate just slightly faster than it is absorbed, maintaining atmospheric pressure and a temperature of approximately 50 C., for 2 hours.

The introduction of hydrogen chloride is then discontinued and the mixture allowed to stand several hours, and dry ammonia gas is introduced under pressure through the tube extending to the bottom of the same reactor or of another reactor containing the product of the preceding reaction, and stirring is continued. When the ammonia is initially introduced, the outlet valve of the reactor is opened slightly so that any air present will be swept out by the incoming ammonia. During this step the gas pressure in the reactor is maintained at about 20 lbs/sq. in. When an atmosphere of substantially pure ammonia has been obtained, the outlet valve is closed and the pressure allowed to 14 rise to from 25 to 50 lbs., where it is maintained for about 18 hours. The temperature is held at a maximum of C. by circulating water, then steam, through the jacket.

After ammoniation is complete, the ammonia pressure is slowly released until atmospheric pressure is reached, and the product is removed from the reactor. The solid ammonium chloride which has formed is removed by filtration and the benzene solution is washed rapidly with water until the washings are substantially free of chlorides. The washing may be carried out in the reactor, but if this is done the latter should preferably be provided with a cone bottom. It the product is to be used as such in a lubricating oil or converted to a salt in oil solution, the required amount of oil may be added to the benzene solution, and

the benzene and any residual water may then be layer may be separated from the benzene layer and the emulsion broken by treatment with live steam until the benzene begins to boil. On standing for an hour or more, a separation of the aqueous and benzene layers will occur. The separated benzene layer may then be returned to the reactor.

The conversion of the product to a metal salt may be carried out in the above benzene solution, or, more preferably, in a mineral oil solution. Thus, to prepare the barium salt 4000 grams of a 50% mineral oil solution of the condensation product obtained as described above are placed in a suitable reaction vessel and heated to C. Then 1600 grams of Ba(OH)2.8H2O are added gradually with stirring over a l to 2 hour period and heating continued for about 30 minutes, after which the product is filtered to give a finished lubricating oil concentrate of the metal salt.

To minimize foaming during the neutralization it is desirable to have present a foam suppressor such as a higher aliphatic alcohol. In a 50% mineral oil concentrate addition of about 3 to 15% of stearyl or cetyl alcohol will greatly minimize foaming and will also facilitate the subsequent filtering operation.

In general, the concentratiori of the salts of the present invention in the extreme pressure agent will vary from 1 to 10% or more, depending upon the amount by which the agent or concentrate is to be diluted with the mineral oil and upon the concentration which it is desired to have in the final blended extreme pressure lubricant. The amounts most generally preferred are 2% to 5% concentrations in materials which are diluted 10-20 times by the base stock, giving a. final concentration of from about 0.1% to about 0.3% of the salt in the final blend.

The following are examples of tests showing the eflectiveness of the corrosion inhibiting agent when blended in a typical extreme pressure agent and freedom from a tendency to form an insoluble reaction product.

Example 10 An extreme pressure lubricant concentrate was prepared according to the method described in U. S. Patent 2,124,598 by heating a chlorinated kerosene containing 40% chlorine (prepared by Q chlorination of kerosene at 200 F. with chlorine gas) with a mixture of sulfur and aqueous sodium hydrosulfide, sodium hydroxide and isopropyl alcohol under reflux for several hours. The reaction mixture was then permitted to settle and a middle layer of the desired reaction product was separated from a lower aqueous layer of inorganic salts and an upper alcoholic layer and then stripped free of alcohol. There was thus obtained a sulfurized chlorinated kerosene containing about 6.1% of sulfur and 32.0% of chlorine.

Example 11 97 grams of a sulfur-chlorine compound containing 6.1% of sulfur and 32.0% chlorine, made by reacting a chlorinated kerosene containing 40% chlorine with sodium polysulfide in an alcohol solution according to the method of Example 10, and 6 grams of a 50% oil concentrate of a barium salt of a condensed alkylated hydroxybenzyl amine, prepared by first preparing the dry hydroxy compound by a method similar to that of Example 1, then dissolving the same in a lubricating oil and treating with barium hydroxide,

using suiiicient lubricating oil to form a 50% solution of the salt (by weight) after refluxing for about 8 hours and filtering, were thoroughly mixed and stored at 120 F. for a period of 60 days. A very small amount of precipitate formed (less than 1%) indicating compatibility of the two materials.

Example 12 Example 13 The composition described in Example 11, after 60 days storage, was blended with the mineral oil used in Example 12 in the same ratio and gave a satisfactory solution. This blend was tested on the Almen testing machine as described in Example 12, and after the 24-hour period of blowing with moist air the test pieces showed only a very slight stain, but indicating satisfactory corrosion prevention.

It is not intended that the invention be limited by any of the particular examples, which have been presented for the purpose of illustration only, but solely by terms of the appended claims.

We claim:

1. A composition suitable for increasing the load-carrying capacity of a mineral lubricating oil which consists essentially of an oil-soluble halogen containing compound of a kind which will substantially increase the load-carrying capacity of the lubricant to which it is added but which tends to forrrr a hydrohalogenic acid in the presence of said oil, and a minor proportion, sumcient to reduce corrosion, of an oil-soluble salt of an autocondensation product of a hydroxyarylalkyl amine, said amine having alkyl groups which contain a total of at least four carbon atoms per molecule.

2. A composition according to claim 1 in which the halogen is chlorine.

3. A composition suitable for increasing the load-carrying capacity of a mineral lubricating oil which consists essentially of a normally liquid aliphatic material, selected from the class consisting of halogenated aliphatic hydrocarbons and substituted products thereof, containing about to about 50% of chlorine and about 3% to about of sulfur, the chlorine and sulfur being in such form as to be capable of substantially increasing the load-carrying capacity of the oil to which it 'may be added but tending to form a hydrohalogenic acid under storage conditions, and a minor proportion, sufiicient to reduce corrosion, of an oil-soluble salt of an autocondensation product of a hydroxyarylalkyl amine, said amine having alkyl groups which I contain a total of at least 4 carbon atoms per molecule.

4. A composition according to claim 3 in which the aliphatic material containing chlorine and sulfur is a petroleum hydrocarbon material.

5. A composition according to claim 3 in which the aliphatic material containing chlorine and sulfur is a petroleum hydrocarbon material of the kerosene boiling range.

6. A composition suitable for increasing the load-carrying capacity of a mineral lubricating oil which consists essentially of an oil-soluble organic halide-of a, kind as to be capable of substantially increasing the load-carrying capacity of the oil to which it may be added but tending to form a, hydrohalogenic acid under storage conditions, and a minor proportion, sufiicient to reduce corrosion, of an oil-soluble salt of an autocondensation product of a hydroxyarylalkyl amine, the uncondensed amine having the characterizing structure in which R is an alkyl linkag and R and R." are hydrogen atoms or alkyl or aryl radicals or substituted alkyl or aryl radicals and n is a small whole number and X is hydrogen or an organic radical.

7. A composition suitable for increasing the load-carrying capacity of a mineral lubricating oil which consists essentially of an oil-soluble organic halide of a kind as to be capable of substantially increasing the load-carrying capacity of the oil to which it may be added but tending to form a hydrohalogenic acid under storage conditions, and a minor proportion, sufficient to reduce corrosion, of a salt of a product obtained by the autocondensation of a hydroxyarylalkyl amine with the elimination of a substantial amount of nitrogen, the uncondensed amine having the general compositional formula wherein R represents at least one alkyl group substituent in the aromatic nucleus Ar, the subscript 12. represents on integer from 1 to 3, and X represents a nitrogen base radical in which the nitrogen is linked to the methylene group or groups.

8. A composition suitable for increasing the load-carrying capacity of a mineral lubricating oil which consists essentially of an oil-soluble organic halide of a kind as to be capable of substantially increasing the load-carrying capacity of the oil to which it may be added but tending to may be added but form a hydrohalogenic acid under storage conditions, and a minor proportion, sumcient to reduce corrosion, of a metal salt of an autocondensation product of an alkyl hydroxy benzylamine having at least 4 carbon atoms in the alkyl group.

9. A composition suitable for increasing the load-carrying capacity of a mineral lubricating oil which consists essentially of an oil-soluble organic halide containing about to about 50% of chlorine and about 3% to about'15% of sulfur, the chlorine and sulfur being in such form as to be capable of substantially increasing the load-carrying capacity of the oil to which it tending to form a hydrohalogenic acid under storage conditions, and a minor proportion, sumcient to reduce corrosion, of a metal salt of an oil-soluble resinous product obtained by the autocondensation of an alkyl hydroxy benzylamine with the elimination of nitrogen, the uncondensed amine having the general compositional formula R- CHrNH:

in which Ris an alkyl group of at least 4 carbon atoms.

10. A composition according to claim '1 in which the salt is a salt of a metal selected from the group consisting of alkali and alkaline earth metals.

11. A composition according to claim 'I in which the salt is a barium salt.

12. A composition suitable for increasing the load-carrying capacity of a mineral lubricatin oil which consists essentially of a petroleum hydrocarbon material of the kerosene boiling range containing about 5% to about 50% of chlorine and about 3% to about 15% of sulfur, the chlorine and sulfur being in such form as to be capable of substantially increasing the load- 1 carrying capacity of the oil to which it may be added but tending to form a hydrohalogenic acid under storage conditions, and a minor proportion, suflicient to reduce corrosion, of an oil-soluble metal salt of a resinous product obtained by the autocondensation of analkyl hydroxy benzylamine with the elimination of nitrogren, the uncondensed amine having the general compositional formula in which R is an alkyl group of at least 4 carbon atoms.

13. A composition according to claim 12 in which the salt is a salt of an alkaline earth metal.

14. An extreme pressure lubricant concentrate which consists essentially of a sulfurized and chlorinated naphtha containing about 5% to about of chlorine and about 3% to about 15% of sulfur and containing a minor proportion, sufficient to reduce corrosion, of an oil-soluble metal salt of an autocondensation product of an ammonium derivative of an alkyl phenol-formaldehyde-hydrogen chloride condensation product in which the alkyl substituent of the phenol contains at least 4 carbon atoms and in which a nitrogen base radical is linked through a methylene group to phenol.

15. A concentrate according to claim 14 in which the alkyl phenol is a tert.-octyl phenol.

16. An extreme pressure lubricant concentrate which consists essentially of a sulfurized and chlorinated naphtha containing about 5% to about 50% of chlorine and about 3% to about 15% of sulfur and containing a minor proportion. sufilcient to reduce corrosion, of a metal salt of a reaction product of an alkylated phenol with ammonia and formaldehyde, the alkyl groups of the said alkyl phenol having a total of at least 4 carbon atoms.

1'7. An extreme pressure lubricant concentrate which consists essentially of a sulfurized and chlorinated naphtha containing about 5% to about 50% of chlorine and about 3% to about 15% of sulfur and containing a minor proportion. suificient to reduce corrosion, of an oil-soluble metal salt of a reaction product of an alkylated phenol with hexamethylenetetramine, the alkyl groups 01' the said alkyl phenol having a total of at least 4 carbon atoms.

18. An extreme pressure lubricant concentrate which consists essentially of a sulfurized and chlorinated kerosene containing about 8 to 7% of sulfur and about 32% of chlorine and containing a minor proportion, sunicient to reduce corrosion of a barium salt of the reaction product of about 4 molecular proportions of diamyl phenol and 1 molecular proportion of hexamethylenetetramine.

JOHN C. zn/mER. GEORGE M. McNUL'I'Y.

REFERENCES CITED The followingrei'erences are of record in the file of this patent:

UNITED STATES PATENTS the aryl nucleus of the alkyl 

